语法专题十三：虚拟语气与情态动词
情态动词和虚拟语气是高考重要考点，《2017年普通高等学校招生全国统一考试大纲》附录语法项目表中列出了虚拟语气以及情态动词。
2015年高考全国卷Ⅰ第79题（短文改错）考查了情态动词must后面接动词原形。 2016年高考全国卷Ⅰ没有考查情态动词与虚拟语气。 2017年高考全国卷Ⅰ没有考查情态动词与虚拟语气。
知 识 框 架
含有条件状语从句的复合句 S.+wish（would rather）+宾语从句 宾语从句 三大板块 虚拟语气 定语从句 S.+suggest（demand …）+宾语从句 名词性从句 主语从句 表语从句 同位语从句 用一般过去表示现在 用过去完成表示过去 用过去将来表示将来 It is + adj./p.p/n.+ that+ S+ (should) +do S.+ is that +s. + (should) +do S.+that +s. +(should) +do It is high/about time that +s.+ should do sth.(did sth) 两种形式 1.时态后退型 2.should+动词原形型 一. 含有条件状语从句的复合句(以do为例;S=主语)
时间 条件状语从句 主 句 现在 If +S+did (were) S+would/should/could/might +do S+would/should/could/might + 过去 If +S+had done have done did(were) 将来 If+S should do were to do S+would/should/could/might +do 例如:
①If I were you, I would apply for the job. ②If I had the money, I would buy it.
③If I were given another chance，I would do it better.
④If I had taken your advice, I would have made great progress.
⑤If it had not been for your help, I wouldn’t have finished the work so easily. ⑥If it should rain tomorrow,I would stay at home all day. ⑦If you were to come tomorrow,I could wait for you at home.
注意：在书面语中，条件从句可以不用连词if，而将谓语中的were，had或 should 等移至主语之前构成倒装句。例如：
①Were I you, I would apply for the job.
②Had I taken your advice, I would have made great progress. ③Should it rain tomorrow,I would stay at home all day. 二、错综时间的条件句
虚拟条件句中的主句和从句涉及的动作发生的时间不一致，这时主句和从句的谓语形式应按照各自动作发生的实际时间来表达。例如：
①If you hadn't watched TV yesterday, you wouldn't be so sleepy now. （从句yesterday说明过去，主句now说明现在）
②If they had left home early this morning, they would arrive in half an hour. （从句说明过去，主句说明将来。）
③If you hesitated this moment, you might suffer in the future. （从句说明现在，主句说明将来） 三、含蓄条件句
非真实条件句中的条件从句有时不表达出来，只暗含在上下文中，这种句子叫做含蓄条件句。含蓄条件句有三种情况： 1．条件暗含在单词短语中：常见介词有with假如有, without假如没有, but for要不是因为； 连词有or/ otherwise（前句用陈述语气，后句用虚拟）；but（前句为虚拟，后句陈述）例如：
①He would not get such a result without your help. (条件暗含在介词短语without your help= if you hadn’t helped him中)
②But for you, I could not be recovered so soon. (条件暗含在But for you= If you hadn’t helped me中) ③He must have been there, or he never could know the place so well.(暗含条件是连词or；后句为虚拟) ④I would have been to your place, but I was really too busy.
=I was really too busy, or/ otherwise I would have been to your place.
⑤She was ill, otherwise she would have been present at the meeting. （条件通过连词otherwise/ or表示出来 If she had not been ill...） 2．条件可根据上下文推理出
①They could have won.(条件可能是if they had been patient )
②Such mistakes could have been avoided.（条件可能是if you had been more careful ）
③Why didn't you tell me about it I should have helped you.（条件可能是if you had told me about it） ④-- Did you go to see him yesterday?
-- I would have, but someone come to visit me.（条件是if no one had come to visit me） 3．条件用其他形式来表示
①Suppose you were in my shoes, what would you do? （用suppose/ supposing/ providing等词表示if） ②To talk with her, you would know she could not hear well.（不定式有假设的意思，相当于If you should talk with her...）
③Left to himself, he could not have finished the work.（动词的-ed形式表示条件 If he had been left to himself...）
二. 虚拟语气用在宾语从句中
sb. did（were）…（表现在） 1. wish+that sb. had done… （表过去） sb. would/could do…（表将来） 例如：
①I wish I knew his address.
②I wish he hadn’t been rude to his parents. ③He wishes we would go with him. 2.would rather后的从句要用虚拟语气。
时 间 从 句 对现在的虚拟 were, did (一般过去时)
对过去的虚拟 had done (过去完成时)
对将来的虚拟 were, did (一般过去时)
例如：
①I’d rather you posted the letter right away. (现在)
②I’d rather I hadn’t said such unkind things to you.（过去） ③I'd rather you came here for the answer tomorrow .（将来）
3. 表示“坚持、建议、决定、要求、命令”（“坚决要命”）等主观意向的动词之后的宾语从句，谓语用should＋do，should可省略(注意：被动语态用should+be+done)。这类词有：insist，suggest，advise，recommend，propose，decide，determine，demand，request，require，desire，order，command等。例如： ①The expert proposed that TV should be turned off at least one hour every day. ②Experiments demand that accurate measurements be made.
③She insisted that we should take up the matter at the meeting. 注意：
1. suggest 表示“暗示、表明”时，用陈述语气。
2. insist 表示“坚持说、坚持认为（某个事实）”时，用陈述语气。例如： ①Your pale face suggests that you are ill. ②He insisted that he hadn’t stolen the money. 三. 虚拟语气用在主语从句中
It is demanded / necessary / a pity + that…等结构的主语从句，谓语动词用should do，should 可省略。 (注意：被动语态用should+be+done)。
可用的词有三类 It +be suggested，ordered，required， that proposed，demanded,requested，S+(should) do